The purpose of the Biobehavioral Methods Core is to enhance the quality of research that focuses on reducing risks in the following vulnerable populations: older adults, children, raciaVethnic minorities, and people with few socioeconomic resources. Specifically, this core was designed to meet the second aim of the CRRVP: strengthen the methodologies used by Center investigators/affiliates and train novices regarding the measurement of biobehavioral variables, management of data, and analysis of data. The aims of the core are to: (a) provide consultation and support for the use of biological measures; (b) provide consultation and support for the measurement of behavioral and experiential measures; (c) provide consultation and services to support data collection, management, analysis, and sharing; and (d) provide programs for development of investigators and project staff with respect to methodological issues. This core was established as part of the existing P20 Center. New expanded services include (a) data collection services for tests of human performance and measures of body composition by dual-energy x-ray absorptiometry; (b) support for qualitative research; (c) interviewer training; and (d) computer progranmling to facilitate data collection in the field setting. The Biobehavioral Methods Core is organized into five components, the first two of which are biological: (a) human performance/body composition; (b) biological markers; (c) behavioral and experiential methods; (d) data management, analysis, and sharing; and (e) investigator development.